This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. xc2xa7119 from an application entitled COLOR SELECTION APPARATUS FOR CATHODE RAY TUBE filed with the Korean Industrial Property Office on Feb. 27, 2001 and there duly assigned Serial No. 2001-9898.
1. Technical Field
The present invention relates to a cathode ray tube, and more particularly, to a color selection apparatus for a cathode ray tube that has a large-sized flat panel.
2. Related Art
A cathode ray tube, the most popular display device, has been developed in various formats while keeping pace with the times. Recently, a wide screen cathode ray tube has been the choice of electronics consumers. In order to enlarge the screen size, the screen panel should be flat in consideration of qualities of the screen images displayed at the periphery of the screen.
As a design for a panel becomes enlarged and flattened, a shadow mask for the color selection apparatus is also enlarged in size. In consideration of various difficulties related to the enlargement of the curved shadow mask such as a weak strength thereof, a new-modeled color selection apparatus has now been employed for use in the cathode ray tube.
Such a color selection apparatus has a structure wherein a mask with a plurality of beam-guide holes is curved in only one direction while bearing a predetermined tension. Exemplars of recent efforts in the art include U.S. Pat. No. 4,926,089 to Moore, entitled TIED SLIT FOIL SHADOW MASK WITH FALSE TIES, issued on May 15, 1990, U.S. Pat. No. 4,942,332 to Adler et al., entitled TIED SLIT MASK FOR COLOR CATHODE RAY TUBES, issued on Jul. 17, 1990, and U.S. Pat. No. 4,973,283 to Adler et al., entitled METHOD OF MANUFACTURING A TIED SLIT MASK CRT, issued on Nov. 27, 1990.
A tension mask has a plurality of slits, with real ties interposed between neighboring slits. The mask is fitted to supporting members while being in a tensioned state. In operation, real ties are liable to be projected onto the screen while producing black lines thereon. The black lines diminish the picture quality of the screen. The real ties frequently cause the black lines on the screen to occur.
While these recent efforts provide advantages, I note that they fail to adequately provide an efficient and convenient color selection apparatus for a large-sized flat panel for a cathode ray tube.
It is an object of the present invention to provide a color selection apparatus for a cathode ray tube that minimizes occurrence of black lines due to real ties and that ensures good picture quality.
This and other objects may be achieved by a color selection apparatus for a cathode ray tube with the following features.
According to one aspect of the present invention, the color selection apparatus includes a mask bearing a shape with short and long axes, and a frame combined with the mask. The mask is fitted to the frame while being tensioned either in the long axis direction or in the short axis direction. The mask has a plurality of strips spaced apart from each other by a predetermined distance, a plurality of real bridges disposed between the neighboring strips with a predetermined pitch while defining beam-guide holes, and one or more dummy bridges placed within each beam-guide hole while being extended from the strips in at least one direction. In any one reference column of m=0 and the other neighboring columns of mxc2x1n (n is a natural number), the real bridges arranged at the reference column are placed at lines different from the real bridges arranged at the columns by at least mxc2x12 in the long axis direction.
According to another aspect of the present invention, the color selection apparatus includes a tension mask having two sides with a first length and another two sides with a second length different from the first length, and a frame for maintaining the tensioned state of the tension mask in a constant manner. The tension mask has a plurality of slit-typed beam-guide holes for passing electron beams such that the electron beams land on a phosphor screen in a correct manner. Dummy bridges are provided within each beam-guide hole while forming a plurality of slits such that the plurality of slits communicate with each other via the dummy bridges. Real bridges define the beam-guide holes such that the beam-guide holes are arranged along each column in the vertical direction. The real bridges arranged at any one column are deviated in position from the real bridges arranged at the neighboring columns in an irregular manner.
To achieve these and other objects in accordance with the principles of the present invention, as embodied and broadly described, the present invention provides a color selection apparatus for a cathode ray tube, comprising: a mask having a length longer than a width, the length being measured in a first direction, the width being measured in a second direction perpendicular to the first direction; and a frame being combined with said mask, said mask being fitted to said frame and being tensioned in one direction selected from among the first and second directions; said mask forming a plurality of real bridges, beam-guide holes, dummy bridges, and strips, the beam-guide holes being formed in a plurality of columns parallel to one direction selected from among the first and second directions, the real bridges being located in the columns, the beam-guide holes being formed parallel to the strips, the strips being spaced apart from each other by a predetermined distance, the real bridges being disposed between adjacent ones of the strips, the real bridges defining the beam-guide holes, at least one of the dummy bridges extending from at least one of the strips into one of the beam-guide holes, the plurality of columns including a reference column and a second column adjacent to the reference column, the real bridges in the reference column being spaced apart from the real bridges in the second column as measured in a direction parallel to the columns.
To achieve these and other objects in accordance with the principles of the present invention, as embodied and broadly described, the present invention provides a color selection apparatus for a cathode ray tube, comprising: a tension mask having a first two sides with a first length, and a second two sides with a second length, the second length being different from the first length; and a frame for maintaining tensioned state of said tension mask in a constant manner; said tension mask having a plurality of slit-type beam-guide holes, dummy bridges, and real bridges, the beam-guide holes passing electron beams toward a phosphor screen, the dummy bridges extending into the beam-guide holes and forming a plurality of slits, the slits being in communication with each other across the dummy bridges, the beam-guide holes being formed in a plurality of columns parallel to a first direction, the real bridges being located in the columns, the real bridges in any one of the columns being displaced along the first direction from the real bridges in adjacent columns.
To achieve these and other objects in accordance with the principles of the present invention, as embodied and broadly described, the present invention provides an apparatus, comprising: a tension mask having a length and a width, the length being measured in a first direction, the width being measured in a second direction perpendicular to the first direction; and a frame being combined with said mask, said mask being fitted to said frame and being tensioned in at least one direction selected from among the first and second directions; said mask including a plurality of real bridges blocking electron beams, beam-guide holes being penetrated by electron beams conveyed to a phosphor screen, dummy bridges at least partially blocking electron beams, and strips blocking electron beams; the beam-guide holes being formed in a plurality of columns parallel to the first direction, the real bridges being located in the columns, the beam-guide holes being formed parallel to the strips, the strips being spaced apart from each other by a predetermined distance, the real bridges being disposed between adjacent ones of the strips, the real bridges defining the beam-guide holes, at least one of the dummy bridges extending from at least one of the strips into one of the beam-guide holes, the plurality of columns including a reference column, a second column, and a third column, the second column being adjacent to the reference column, the third column being adjacent to the second column and spaced apart from the reference column, the real bridges in the reference column being spaced apart from the real bridges in the second column by a first distance as measured in a direction parallel to the first direction, the real bridges in the reference column being spaced apart from the real bridges in the third column by a second distance as measured in a direction parallel to the first direction, the second distance being less than the first distance, each dummy bridge having a vertical width Dhw, each real bridge having a vertical width Rhw, Dhw being  less than =2 Rhw, and Dhw being  greater than =0.5 Rhw.
The present invention is more specifically described in the following paragraphs by reference to the drawings attached only by way of example. Other advantages and features will become apparent from the following description and from the claims.